The present invention relates to a cutting tool having two edge-on mounted inserts that is capable of performing cutting operations by means of an overlapping configuration of the cutting inserts.
Cutting tools having edge-on mounted inserts are known. Such a tool is shown, for example, in U.S. Pat. No. 5,529,440 to Schmidt. As shown in ""440, a single cutting insert is mounted edge-on on a front end of a blade. When performing parting or slotting operations with such a tool, the width of the slot is limited to the width of the operative cutting edge of the cutting insert.
Another tool having edge-on mounted inserts is shown in Japanese Publication Number 06262422 A to Naoaki. As shown in FIG. 6 of ""422, the cutting inserts are alternatingly arranged on the periphery of a disc body. The described arrangement enables overlapping of the operative cutting edges of succeeding cutting inserts for obtaining a wider slot than can be obtained by a single cutting insert.
Such a tool suffers from the disadvantage that if an insert pocket breaks due to a breakage of a cutting insert than it is necessary to replace the entire disc body. Furthermore, in such a tool, the cutting diameter is fixed and depends on the diameter of the disc body.
It is an object of the present invention to provide a cutting tool that significantly reduces or overcomes the aforementioned disadvantages.
It is a further object of the present invention to provide a cutting tool to part a fixed pipe by cutting around it without being limited by the diameter of the pipe.
In accordance with the present invention there is provided a cutting tool comprising a blade and two cutting inserts mounted therein,
the blade having a front insert retaining portion and a rear body portion, defining a front to rear longitudinal direction (A), a right side and a left side extend between an upper side and a lower side, the right side and the left side facing opposing directions, the opposing directions being transverse to the front to rear longitudinal direction;
the insert retaining portion having a right side face and an oppositely directed left side face and comprising an upper insert receiving pocket, upwardly located with respect to a lower insert receiving pocket, and a rearwardly extending recess between the upper and lower insert receiving pockets;
each one of the two insert receiving pockets comprises a rear wall, transversely directed to the longitudinal direction (A) and substantially perpendicular to the right and left side faces, a lower wall adjacent to the rear wall and substantially perpendicular to the right and left side faces, a side wall that is substantially perpendicular to the rear and lower walls, and, a threaded bore extending from the side wall to an adjacent of the right and left side faces, the side wall of one of the two insert receiving pockets faces generally in the same direction as the right side of the blade and the side wall of the other of the two insert receiving pockets faces generally in the same direction as the left side of the blade;
each one of the two cutting inserts has a top surface, a bottom surface and a side surface connecting the top and bottom surfaces, at least one cutting edge extends on the side surface substantially between the top and bottom surfaces, a through bore extends between the top and bottom surfaces;
each one of the two cutting inserts is located within a different one of the insert receiving pockets such that the insert bottom surface abuts the side wall of the insert receiving pocket and the cutting insert is retained by a clamping screw that passes through the through bore and threadingly engages the threaded bore.
According to a specific embodiment of the present invention, the side wall of each of the insert receiving pockets is slanted at an acute angle (xcex4) with respect to an adjacent side face of the insert retaining portion.
Typically, the slant angle (xcex4) is 2xc2x0.
Typically, the side wall of a first of the two insert receiving pockets is adjacent the right side face of the insert retaining portion and the side wall of a second of the two insert receiving pockets is adjacent the left side face of the insert retaining portion.
Generally, the body portion extends rearwardly from the insert retaining portion in the longitudinal direction (A), the body portion being generally prismoidal in shape, having a right side face and a left side face connected by top and bottom faces.
Typically, the right side face of the body portion is parallel to the left side face of the body portion.
Further typically, the top face is parallel to the bottom face in a side view of the blade.
Preferably, a distance (W) between the right and left side faces of the body portion is substantially smaller than a height dimension (H1) between the top and bottom faces.
According to a specific embodiment of the present invention, the top face and the bottom face are slanted at an acute angle (xcex1) with respect to the left side face of the body portion.
Preferably, the insert retaining portion has a height dimension (H2) that is larger than the height dimension (H1) between the top and bottom faces of the body portion.
Generally, the lower walls of each of the insert receiving pockets define therebetween an internal acute angle (xcex2).
Typically, the internal acute angle (xcex2) is in the range of 0xc2x0 to 50xc2x0.
Further typically, the threaded bore is substantially perpendicular to the adjacent of the side faces of the insert retaining portion.
Generally, each of the two cutting inserts has a polygonal shape.
According to a specific embodiment of the present invention, each of the two cutting inserts has two pairs of diametrically opposed identical cutting edges.
Preferably, in a front view of the cutting tool the two cutting edges overlap between planes (P5, P6) passing through inner extremities of the cutting edges and parallel to the side faces of the insert retaining portion.
Further preferably, each of the two cutting inserts protrudes outwardly with respect to a side face of the blade adjacent the top surface of the cutting insert.
Typically, the at least one cutting edge of each of the two cutting inserts is equally distanced from an apex (Q) of the internal acute angle (i).
Generally, the cutting tool has a cutting width (W1) between 6 to 10 mm.
Typically, the body portion is integrally connected to the insert retaining portion.
According to a specific embodiment of the present invention, the two cutting inserts are identical.
Typically, each of the cutting inserts is made of cemented carbide.
Further typically, the blade is made of tool steel.
There is also provided in accordance with the present invention, a cutting tool assembly comprising a plurality of cutting tools according to the present invention, wherein the plurality of the cutting tools are clamped on an annular disc having an axis of rotation (O), each of the cutting edges being equally distanced from the axis of rotation (O).
Preferably, the plurality of the cutting tools are equally peripherally distributed on an end face of said disc.
Typically, the insert retaining portion of each of the cutting tools is inwardly directed with respect to the axis of rotation (O).